JP2023010256A - Motor control device and power conversion device - Google Patents

Abstract

To provide a motor control device and a power conversion device that can improve the accuracy of motor control.SOLUTION: A control device performs motor control processing. The control device acquires detected currents Iu, Iv, and Iw as current acquisition values in a motor control processing step S102. In step S103, the control device determines whether it is in a zero-cross state. If it is not in the zero-cross state, the control device 40 proceeds to step S104 to set the detected currents Iu, Iv, and Iw as calculated currents Iup, Ivp, and Iwp. If it is in the zero-cross state, the control device 40 proceeds to step S105 to generate filter currents Iuf, Ivf, and Iwf from the detected currents Iu, Iv, and Iw by filtering processing. In step S106, the control device 40 sets the filter currents Iuf, Ivf, and Iwf as the calculated currents Iup, Ivp, Iwp.SELECTED DRAWING: Figure 9

Description

The disclosure in this specification relates to motor controllers and power converters.

Patent Document 1 discloses a motor control device that controls a motor. This motor control device has a current sensing element and a filter. A current sensing element senses the current flowing through the motor. The filter removes noise from the detection signal of the current detection element. Patent Document 1 states that the filter improves the accuracy of detecting the current flowing through the motor.

Japanese Patent No. 6050841

However, in Patent Document 1, if ripple occurs in the current flowing through the motor, there is concern that the detected current value will vary in the amplitude direction of the ripple, resulting in a decrease in motor control accuracy. If the control accuracy of the motor is lowered, it is conceivable that the driving noise and vibration of the motor will increase.

A main object of the present disclosure is to provide a motor control device and a power conversion device that can improve the accuracy of motor control.

The multiple aspects disclosed in this specification employ different technical means to achieve their respective objectives. In addition, the symbols in parentheses described in the claims and this section are an example showing the correspondence relationship with the specific means described in the embodiment described later as one aspect, and limit the technical scope is not.

In order to achieve the above object, the disclosed first aspect includes:
A motor control device (40) for controlling a motor (12) with command voltages (Vd*, Vq*),
a current acquisition unit (S102) that acquires currents flowing through the motor as current acquisition values (Iu, Iv, Iw);
a voltage command unit (56, S108) that calculates the command voltage using the current acquisition value as calculation parameters (Iup, Ivp, Iwp) for calculating the command voltage;
a filter unit (63, S105) that acquires filtered currents (Iuf, Ivf, Iwf) from the acquired current values by filtering to reduce pulsation of the acquired current values;
a calculation setting unit (S106) that sets the filter current as a calculation parameter in a zero-crossing state including the zero-crossing of the current acquisition value;
A motor control device comprising

According to the first aspect, in the zero-crossing state, the filter current whose pulsation is reduced with respect to the current acquisition value is set as the calculation parameter for calculating the command voltage. Therefore, in the zero-crossing state, the use of the filter current to calculate the command voltage makes it difficult for the calculation accuracy of the command voltage to decrease due to the large pulsation of the current acquisition value. Thus, in the zero-crossing state, the motor control is less susceptible to large ripples in the current acquisition. Therefore, it is possible to suppress a decrease in the accuracy of motor control in the zero-cross state, and as a result, it is possible to improve the accuracy of motor control. By increasing the accuracy of motor control, it is possible to suppress an increase in motor drive noise and vibration.

A second aspect is
A power conversion device (13) for converting power supplied to a motor (12),
a motor control device (40) for controlling the motor with command voltages (Vd*, Vq*);
The motor control device
a current acquisition unit (S102) that acquires currents flowing through the motor as current acquisition values (Iu, Iv, Iw);
a voltage command unit (56, S108) that calculates the command voltage using the current acquisition value as calculation parameters (Iup, Ivp, Iwp) for calculating the command voltage;
a filter unit (63, S105) that acquires filtered currents (Iuf, Ivf, Iwf) from the acquired current values by filtering to reduce pulsation of the acquired current values;
a calculation setting unit (64, S106) that sets the filter current as a calculation parameter in a zero-crossing state including the zero-crossing of the current acquisition value;
It is a power conversion device having

According to the second aspect, the same effects as those of the first aspect can be obtained.

The figure which shows the structure of the drive system in 1st Embodiment. 2 is a block diagram showing the electrical configuration of a control device in the drive system; FIG. FIG. 2 is a block diagram showing the electrical configuration of a current setting section in the drive system; FIG. 4 is a diagram showing actual currents and detected currents of U-phase, V-phase, and W-phase; The enlarged view of the arrow V part of FIG. FIG. 5 is an enlarged view of an arrow VI portion of FIG. 4; FIG. 5 is an enlarged view of the arrow VII portion of FIG. 4, showing the vicinity of the zero crossings of the U-phase actual current and the U-phase detected current; FIG. 4 is a diagram showing respective filter currents of U-phase, V-phase, and W-phase; 4 is a flowchart showing the procedure of motor control processing; The figure which compared the tertiary one-sided amplitude of d-axis current and q-axis current by a control apparatus and a comparative example. FIG. 5 is a block diagram showing the electrical configuration of a voltage command section in the drive system according to the second embodiment; FIG. 4 is a diagram showing respective filter currents of U-phase, V-phase, and W-phase; FIG. 13 is an enlarged view of the arrow XIII portion of FIG. 12; 4 is a flowchart showing the procedure of motor control processing; FIG. 11 is a block diagram showing the electrical configuration of a voltage command section in the drive system according to the third embodiment; FIG. 5 is a diagram showing the vicinity of the zero crossing of the phase angle in the U-phase actual current and the U-phase detected current;

A plurality of modes for carrying out the present disclosure will be described below with reference to the drawings. In each form, the same reference numerals may be given to the parts corresponding to the matters described in the preceding form, and overlapping explanations may be omitted. When only a part of the configuration is described in each form, the previously described other forms can be applied to other parts of the configuration. Not only combinations of parts that are explicitly stated that combinations are possible in each embodiment, but also partial combinations of embodiments even if they are not explicitly stated unless there is a particular problem with the combination. is also possible.

<First Embodiment>
A drive system 10 shown in FIG. 1 is mounted in a vehicle such as an electric vehicle EV, a hybrid vehicle HV, or a fuel cell vehicle. The drive system 10 has a battery 11 , a motor 12 and a power conversion device 13 . The drive system 10 is a system that drives a motor 12 to drive the drive wheels of the vehicle.

The battery 11 is a DC voltage source composed of a chargeable/dischargeable secondary battery, and corresponds to a power source that supplies power to the motor 12 via the power conversion device 13 . Secondary batteries are, for example, lithium-ion batteries and nickel-metal hydride batteries. The battery 11 supplies the inverter 30 with a high voltage of several hundred volts, for example.

The motor 12 is a multi-phase AC motor, such as a three-phase AC rotary electric machine. The motor 12 has U phase, V phase, and W phase as three phases. The motor 12 functions as an electric motor that is a drive source for the vehicle. The motor 12 functions as a generator during regeneration. The motor 12 has windings 12a forming an armature and permanent magnets forming a magnetic field. In this motor 12, a rotor is configured including permanent magnets, and a stator is configured including windings 12a. The motor 12, which is a three-phase motor, has three-phase windings 12a. The motor 12 is sometimes called a motor generator or an electric motor.

The power conversion device 13 converts power between the battery 11 and the motor 12 . The power conversion device 13 has a smoothing capacitor 21 , an inverter 30 and a control device 40 . In FIG. 1, the controller 40 is illustrated as CD.

Smoothing capacitor 21 smoothes the DC voltage supplied from battery 11 . The smoothing capacitor 21 is connected to a P line 25 that is a power line on the high potential side and an N line 26 that is a power line on the low potential side. The P line 25 is connected to the positive terminal of the battery 11 and the N line 26 is connected to the negative terminal of the battery 11 . The positive electrode of smoothing capacitor 21 is connected to P line 25 between battery 11 and inverter 30 . Further, the negative electrode of smoothing capacitor 21 is connected to N line 26 between battery 11 and inverter 30 . Smoothing capacitor 21 is connected in parallel with battery 11 . In the power conversion device 13, the P line 25 and the N line 26 are formed by busbars or the like.

A switch (not shown) is provided between the battery 11 and the smoothing capacitor 21 in the power converter 13 . The switch electrically connects the battery 11 and the inverter 30 . A switch is a system main relay and is provided on at least one of the P line 25 and the N line 26 . When the switch is closed, power is supplied from the battery 11 to the inverter 30 and the motor 12 . When the switch is in the open state, power supply from the battery 11 to the inverter 30 and the motor 12 is cut off.

The inverter 30 converts the power supplied from the battery 11 to the motor 12 from direct current to alternating current. The inverter 30 is a three-phase inverter and performs power conversion for each of the three phases. Inverter 30 corresponds to a power converter. Inverter 30 converts a DC voltage into an AC voltage according to switching control by control device 40 and outputs the AC voltage to motor 12 . Motor 12 operates to generate a predetermined rotational torque according to the AC voltage from inverter 30 . Inverter 30 converts AC voltage generated by motor 12 in response to rotational force from the drive wheels during regenerative braking of the vehicle into DC voltage in accordance with switching control by control device 40 , and outputs the voltage to battery 11 . . Inverter 30 performs bidirectional power conversion between battery 11 and motor 12 .

The inverter 30 is a DC-AC conversion circuit. The inverter 30 is configured with upper and lower arm circuits 31 for three phases. The upper and lower arm circuits 31 are sometimes called legs. The upper and lower arm circuits 31 each have an upper arm 31a and a lower arm 31b. The upper arm 31a and the lower arm 31b are connected in series between the P line 25 and the N line 26 with the upper arm 31a on the P line 25 side. A connection point between the upper arm 31 a and the lower arm 31 b is connected to the corresponding phase winding 12 a of the motor 12 via an output line 27 . The upper and lower arm circuits 31 and output lines 27 are provided for each of the U-phase, V-phase, and W-phase of the motor 12 . The inverter 30 has three upper arms 31a and three lower arms 31b.

The arms 31a, 31b have arm switches 32a, 32b and diodes 33a, 33b. The upper arm 31a has one upper arm switch 32a and one upper diode 33a. The lower arm 31b has one lower arm switch 32b and one lower diode 33b.

The arm switches 32a and 32b are formed of switching elements such as semiconductor elements. This switching element is a transistor having a gate, and is formed of, for example, IGBT or MOSFET. In this embodiment, for example, the arm switches 32a and 32b are formed of n-channel IGBTs. Diodes 33a and 33b are diodes for freewheeling, and are connected in anti-parallel to arm switches 32a and 32b.

The collector of the upper arm switch 32a is connected to the P line 25 in the upper arm 31a. The emitter of the lower arm switch 32b is connected to the N line 26 in the lower arm 31b. The emitter of the upper arm switch 32a and the collector of the lower arm switch 32b are connected to each other. The anodes of the diodes 33a, 33b are connected to the emitters of the corresponding arm switches 32a, 32b, and the cathodes are connected to the collectors.

As shown in FIG. 3 , the power converter 13 has a noise filter 35 . Noise filter 35 is provided between battery 11 and inverter 30 . Noise filter 35 regulates the application of noise from inverter 30 to battery 11 . Even if noise occurs in the inverter 30 due to driving of the arm switches 32 a and 32 b , the noise transmitted from the inverter 30 to the battery 11 is reduced by the noise filter 35 . The noise filter 35 has a filter coil 35a. Filter coil 35 a is provided on P line 25 between battery 11 and smoothing capacitor 21 . The noise filter 35 is sometimes called a power supply side filter.

The control device 40 is an ECU, for example, and controls driving of the inverter 30 . ECU is an abbreviation for Electronic Control Unit. The control device 40 is mainly composed of a microcomputer (hereinafter referred to as a microcomputer) having, for example, a processor, memory, I/O, and a bus connecting them. Control device 40 executes various processes related to driving inverter 30 by executing a control program stored in the memory. This memory is a non-transitional physical storage medium that non-temporarily stores computer-readable programs and data. A non-transitional tangible storage medium is a non-transitory tangible storage medium, which is implemented by a semiconductor memory, a magnetic disk, or the like.

The control device 40 generates a drive command using signals input from a host ECU such as an integrated ECU mounted on the vehicle and signals input from various sensors such as the rotation sensor 29 . Then, the control device 40 causes the arm switches 32a and 32b to be turned on or off in response to this drive command. The arm switches 32a and 32b are capable of transitioning between an on state and an off state, transitioning to the on state with on-drive, and transitioning to the off state with off-drive. As for the arm switches 32a and 32b, the ON state corresponds to the closed state, and the OFF state corresponds to the open state.

A current sensor 28 and a rotation sensor 29 are electrically connected to the control device 40 as various sensors. Both current sensor 28 and rotation sensor 29 are included in drive system 10 . Current sensor 28 is included in power converter 13 .

The current sensor 28 is a current detector that detects current flowing through the motor 12 . Current sensor 28 outputs to control device 40 a detection signal corresponding to the current flowing through each of three-phase windings 12a. A current sensor 28 is provided for at least one of the output lines 27, for example. Current sensor 28 detects the current flowing through winding 12 a by detecting the current flowing through output line 27 . The current sensor 28 discretely samples the current flowing through the winding 12a at a predetermined sampling period and outputs discrete signals as detection signals. The current flowing through the winding 12a is sometimes called an armature current.

The rotation sensor 29 is provided in the motor 12 and is a rotation detection section that detects the number of rotations of the motor 12 . The rotation sensor 29 outputs a detection signal corresponding to the rotation speed of the motor 12 to the control device 40 . The rotation sensor 29 includes, for example, an encoder, a resolver, and the like.

The control device 40 performs vector control of the motor 12 via the inverter 30 . In vector control, three-phase AC coordinates indicated by U-phase, V-phase, and W-phase are converted into dq coordinates indicated by d-axis and q-axis. The dq coordinates are rotational coordinates defined by the d-axis and the q-axis, for example, with the direction from the S pole to the N pole of the rotor being the d-axis and the direction perpendicular to the d-axis being the q-axis. Vector control of the motor 12 is one type of motor control, and motor control is sometimes called inverter control or power conversion control. The control device 40 corresponds to a motor control device.

As shown in FIG. 2, the control device 40 includes, as functional blocks, a current setting unit 61, a current command unit 51, a three-phase to two-phase conversion unit 52, a d-axis subtraction unit 53, a q-axis subtraction unit 54, and a current control unit 55. , a two-to-three phase converter 56 . The functional block may be configured in hardware by at least one IC or the like, or may be executed by a combination of software execution by a processor and hardware. 2, the motor 12 is M, the current sensor 28 is CS, the rotation sensor 29 is RS, the inverter 30 is INV, and the current setting unit 61 is CMU. Also, the current command unit 51 is shown as CCU, the three-phase two-phase conversion unit 52 as uvw/dq, the current control unit 55 as FBU, and the two-phase three-phase conversion unit 56 as dq/uvw.

Detected currents Iu, Iv, and Iw detected by the current sensor 28 are input to the three-phase to two-phase converter 52 . The detected currents Iu, Iv, and Iw are detected values of currents actually flowing through the windings 12a of the respective phases in the motor 12. FIG. The U-phase detection current Iu is a current detection value for the U-phase winding 12a. The V-phase detection current Iv is a current detection value for the V-phase winding 12a. The W-phase detection current Iw is a current detection value for the W-phase winding 12a. The detected currents Iu, Iv, and Iw correspond to current acquisition values. The control device 40 has a current acquisition section that acquires the detected currents Iu, Iv, and Iw using the detection signal of the current sensor 28 . This current acquisition section may be included in the three-phase to two-phase conversion section 52 .

A current setting unit 61 sets the calculated currents Iup, Ivp, and Iwp. The calculated currents Iup, Ivp, and Iwp are calculation parameters for calculating a d-axis command voltage Vd* and a q-axis command voltage Vq*, which will be described later. Current setting unit 61 calculates calculated currents Iup, Ivp, and Iwp using detected currents Iu, Iv, and Iw. Current setting unit 61 outputs calculated currents Iup, Ivp, and Iwp to three-to-two phase conversion unit 52 .

The calculated currents Iup, Ivp, and Iwp set by the current setting unit 61 are input to the three-phase to two-phase conversion unit 52 . The motor rotation speed Nm and the like are input to the three-phase to two-phase conversion unit 52 as detection results of the rotation sensor 29 . The motor rotation speed Nm is a detected value indicating the actual rotation speed of the motor 12 . The motor rotation speed Nm is, for example, the rotation speed of the motor 12 per unit time, and is a value indicating the rotation speed. The control device 40 acquires the rotation angle of the motor 12 as an electrical angle θ and a mechanical angle using the detection signal of the rotation sensor 29 . The electrical angle θ indicates the phase of the current flowing through the winding 12a in each phase and the phase of the voltage applied to the winding 12a in each phase. The electrical angles θ of the detected currents Iu, Iv and Iw are the phase angles θu, θv and θw. U-phase angle θu indicates the phase of U-phase detection current Iu. V-phase angle θv indicates the phase of V-phase detection current Iv. W-phase angle θw indicates the phase of W-phase detection current Iw. The phase angles θu, θv, θw correspond to rotation angles.

The three-phase to two-phase converter 52 calculates the d-axis current Id and the q-axis current Iq by coordinate-transforming the calculated currents Iup, Ivp, and Iwp. The calculated currents Iup, Ivp, and Iwp are currents in the three-phase AC coordinate system, and the d-axis current Id and the q-axis current Iq are currents in the dq coordinate system. The d-axis current Id is a component along the d-axis in the dq coordinates, and the q-axis current Iq is a component along the q-axis in the dq coordinates. The three-phase to two-phase converter 52 calculates the d-axis current Id and the q-axis current Iq using the motor rotation speed Nm in addition to the calculated currents Iup, Ivp, and Iwp. For example, the three-phase to two-phase converter 52 converts the calculated currents Iup, Ivp, and Iwp into dq coordinates based on the motor rotation speed Nm to calculate the d-axis current Id and the q-axis current Iq. The d-axis current Id and the q-axis current Iq are input to the d-axis subtraction section 53 . Note that the three-phase to two-phase conversion unit 52 corresponds to the coordinate conversion unit. The d-axis current is sometimes called the field current, and the q-axis current is sometimes called the drive current.

The current command unit 51 sets target values of the d-axis current Id and the q-axis current Iq as the d-axis command current Id* and the q-axis command current Iq*, respectively. The d-axis command current Id* is input to the d-axis subtractor 53, and the q-axis command current Iq* is input to the q-axis subtractor . A torque command value as a rotational torque to be generated by the motor 12 is input to the current command unit 51 as a signal from the host ECU. The current command unit 51 calculates a d-axis command current Id* and a q-axis command current Iq* according to a torque command value or the like when power is being supplied from the battery 11 to the motor 12 or the like. A motor rotation speed Nm or the like is input to the current command unit 51 as information about the electrical angle θ.

The d-axis subtraction unit 53 calculates the deviation between the d-axis command current Id* and the d-axis current Id as the d-axis current deviation. The q-axis subtraction unit 54 calculates the deviation between the q-axis command current Iq* and the q-axis current Iq as the q-axis current deviation. These d-axis current deviation and q-axis current deviation are input to the current control section 55 .

The current control unit 55 calculates the d-axis command voltage Vd* so that the d-axis current deviation becomes zero, and calculates the q-axis command voltage Vq* so that the q-axis current deviation becomes zero. The current control unit 55 performs feedback control so that the d-axis current Id matches the d-axis command current Id* to calculate the d-axis command voltage Vd*. Further, the current control unit 55 performs feedback control so that the q-axis current Iq matches the q-axis command current Iq* to calculate the q-axis command voltage Vq*. The current control unit 55 performs, for example, PI control as feedback control. The current control unit 55 inputs the d-axis command voltage Vd* and the q-axis command voltage Vq* to the two-to-three phase conversion unit 56 . The current control section 55 corresponds to the dq reference command section.

The d-axis command voltage Vd* is a command value for the d-axis voltage in the dq coordinate system. The q-axis command voltage Vq* is a command value for the q-axis voltage. The d-axis voltage is a component in the d-axis direction on the d-axis coordinates. The q-axis voltage is a component in the q-axis direction. The current control unit 55 calculates the d-axis command voltage Vd* and the q-axis command voltage Vq* for each voltage phase using, for example, a predetermined arithmetic expression. The d-axis command voltage Vd* and the q-axis command voltage Vq* correspond to command voltages. Note that the motor rotation speed Nm, the electrical angle θ, and the mechanical angle are all parameters that indicate the rotation state and drive state of the motor 12 .

A two-to-three-phase conversion unit 56 coordinates-converts the d-axis command voltage Vd* and the q-axis command voltage Vq* in the dq coordinate system to three-phase AC coordinates, and converts the U-phase command voltages Vu* and V in the three-phase coordinate system. A phase command voltage Vv* and a W-phase command voltage Vw* are calculated. These phase command voltages Vu*, Vv*, Vw* are voltage values to be output to the three-phase windings 12a, respectively, and are information included in the drive command. A drive command including these phase command voltages Vu*, Vv*, Vw* is input to inverter 30 . The two-to-three phase conversion section 56 corresponds to the command section.

As shown in FIG. 4, pulsations may occur in the actual currents IuR, IvR, and IwR. The actual currents IuR, IvR, and IwR are currents that actually flow through the motor 12 . The U-phase actual current IuR is the current that actually flows through the U-phase winding 12a. The V-phase actual current IvR is the current that actually flows through the V-phase winding 12a. The W-phase actual current IwR is a current that actually flows through the W-phase winding 12a. The pulsation of the actual currents IuR, IvR and IwR is considered to be caused by driving the arm switches 32a and 32b. The actual currents IuR, IvR, IwR are sometimes referred to as analog values. The actual currents IuR, IvR, and IwR shown in FIG. 4 are waveforms obtained by simulation or the like.

The detected currents Iu, Iv, Iw are detected values sampled from the actual currents IuR, IvR, IwR. The timings for detecting the detected currents Iu, Iv and Iw correspond to the pulsation frequencies of the actual currents IuR, IvR and IwR. For example, the timing of detecting the detection currents Iu, Iv, Iw is synchronized with the carrier frequency. That is, the timing of detecting the detected currents Iu, Iv, and Iw is synchronized with the command signal generated by the signal generator 44 .

Like the U-phase actual current IuR shown in FIG. 5, values close to the average values of the actual currents IuR, IvR, and IwR are detected as the detection currents Iu, Iv, and Iw in one cycle of the actual current ripple. there is The real current ripple is the pulsating component contained in the real currents IuR, IvR, and IwR. The average values of the actual currents IuR, IvR, and IwR are intermediate values between the maximum value CRmax and the minimum value CRmin in one period of the actual current ripple. An electrical angle θ [rad] corresponding to the timing of detecting the detected currents Iu, Iv, and Iw is called a detected angle. In this case, since the period of the detected angle is a period corresponding to the carrier period, the detected currents Iu, Iv and Iw tend to be close to the average values of the actual currents IuR, IvR and IwR.

Detection deviation may occur in the detection currents Iu, Iv, and Iw. The detection deviation is the deviation of the detected currents Iu, Iv, Iw from the average values of the actual currents IuR, IvR, IwR. It is considered that the detection deviation is caused by the actual current ripple and the detected current ripple. The detected currents Iu, Iv, and Iw may also pulsate in the same way as the actual currents IuR, IvR, and IwR. The detected current ripple is the pulsating component contained in the detected currents Iu, Iv, and Iw. The larger the actual current ripple and the detected current ripple, the larger the detection deviation.

The magnitude of the detection deviation may vary depending on the magnitude of the detection currents Iu, Iv, and Iw and the electrical angle θ. For example, in one cycle of the detection currents Iu, Iv, and Iw, the detection deviation tends to be relatively small near the peak and near the bottom, as shown in FIG. On the other hand, in one cycle of the detection currents Iu, Iv, and Iw, near the zero crossing, as shown in FIG. 6, the detection deviation tends to be relatively large. Also, near the zero cross, the detected currents Iu, Iv, and Iw tend to be smaller than the average value of the actual current ripples. A possible reason for the large detection deviation near the zero cross is that the dead time is set. Note that the detection deviation is sometimes called a detection error.

As shown in FIG. 3, the current setting section 61 has a zero cross determination section 62, a current filter 63, and a current switching section 64 as functional blocks. In FIG. 3, the zero-cross determination unit 62 is shown as ZIS, the current filter 63 as CF, the current switching unit 64 as CSS, the signal generation unit 44 as SG, and the dead time setting unit 44a as DTS.

The detected currents Iu, Iv, and Iw are input to the zero-cross determination unit 62 . Information about the electrical angle θ is input to the zero-cross determination unit 62 as the detection result of the rotation sensor 29 . The zero-cross determination unit 62 performs zero-cross determination. The zero-cross determination unit 62 determines whether or not the drive state of the motor 12 is in the zero-cross state as the zero-cross determination. The zero-crossing state is a state including zero-crossings of the detection currents Iu, Iv, and Iw. The zero crossing of the detected currents Iu, Iv, Iw means that one of the detected currents Iu, Iv, Iw becomes zero, and is sometimes referred to as current zero crossing. In the zero-cross state, the detected currents Iu, Iv, Iw are in the current zero-cross range ZI (see FIG. 4). The zero-cross determination unit 62 determines whether or not the detected currents Iu, Iv, and Iw are within the current zero-cross range ZI.

The zero-cross determination section 62 outputs the determination result of the zero-cross determination to the current switching section 64 . The zero-cross determination section 62 corresponds to a parameter determination section and a current determination section. The zero-cross determination section 62 is sometimes called a current zero-cross determination section. The current zero-cross range ZI is sometimes simply called a zero-cross range or a zero-cross section.

The detection currents Iu, Iv, and Iw are input to the current filter 63 . The current filter 63 can reduce detection current ripples contained in the detection currents Iu, Iv, and Iw. The current filter 63 corresponds to the filter section. The current filter 63 can reduce pulsation of the detected currents Iu, Iv and Iw. The current filter 63 has a digital filter such as a low-pass filter. As a digital filter forming the current filter 63, a bandpass filter, a moving average, or the like may be used. The current filter 63 filters the detected currents Iu, Iv, and Iw using a digital filter.

The current filter 63 generates filtered currents Iuf, Ivf and Iwf from the detected currents Iu, Iv and Iw by filtering. Current filter 63 generates U-phase filter current Iuf from U-phase detection current Iu, V-phase filter current Ivf from V-phase detection current Iv, and W-phase filter current Iwf from W-phase detection current Iw. Like the U-phase filter current Iuf shown in FIG. 8, the filter currents Iuf, Ivf and Iwf have smaller pulsations than the detection currents Iu, Iv and Iw. That is, the filter currents Iuf, Ivf, Iwf have smaller current ripples than the detection currents Iu, Iv, Iw. Current filter 63 outputs filter currents Iuf, Ivf, and Iwf to current switching unit 64 .

The filter currents Iuf, Ivf, and Iwf have smaller current ripples than the detected currents Iu, Iv, and Iw, and thus approximate the average values of the actual currents IuR, IvR, and IwR. Even in this case, filter deviation may occur in the filter currents Iuf, Ivf, and Iwf. The filter deviation is the deviation of the filter currents Iuf, Ivf, Iwf from the average values of the actual currents IuR, IvR, IwR. The filter deviation is smaller than the detection deviation. This is because the filter currents Iuf, Ivf, and Iwf virtually approximate the average values of the actual currents IuR, IvR, and IwR by reducing the pulsation of the actual currents IuR, IvR, and IwR.

As shown in FIG. 3, the current switching unit 64 receives the detected currents Iu, Iv, Iw, the determination result of the zero-crossing determination, and the filter currents Iuf, Ivf, Iwf. The current switching unit 64 switches the calculated currents Iup, Ivp, Iwp to the detection currents Iu, Iv, Iw or the filter currents Iuf, Ivf, Iwf according to the determination result of the zero-crossing determination. Current switching unit 64 sets filter currents Iuf, Ivf, and Iwf as calculated currents Iup, Ivp, and Iwp in the zero-crossing state. The current switching unit 64 sets the detected currents Iu, Iv and Iw as the calculated currents Iup, Ivp and Iwp when the zero-crossing state is not in effect. Current switching unit 64 outputs calculated currents Iup, Ivp, and Iwp to three-to-two phase conversion unit 52 .

The control device 40 has a signal generator 44 . The phase command voltages Vu*, Vv*, Vw* are input from the two-to-three-phase converter 56 to the signal generator 44 . The signal generator 44 generates command signals using the phase command voltages Vu*, Vv*, Vw*. The signal generator 44 compares the phase command voltages Vu*, Vv*, Vw* with the carrier, and generates pulse-shaped command signals for each of the U-phase, V-phase, and W-phase. A pulse-shaped command signal is, for example, a PWM signal. The command signal is synchronous with the carrier frequency. Control device 40 drives inverter 30 according to the command signal generated by signal generator 44 .

The signal generation section 44 has a dead time setting section 44a. The dead time setting unit 44a sets dead times for each of the U phase, V phase, and W phase. The dead time is a period during which the upper arm switch 32a and the lower arm switch 32b are simultaneously off in the upper and lower arm circuits 31 of the U-phase, V-phase, and W-phase, respectively. By setting the dead time by the dead time setting unit 44a, the situation in which the upper arm switch 32a and the lower arm switch 32b are turned on at the same time in each of the U phase, V phase, and W phase is avoided. That is, a short circuit in the upper and lower arm circuits 31 is avoided.

As described above, the current setting unit 61 sets the filter currents Iuf, Ivf, and Iwf as the calculated currents Iup, Ivp, and Iwp in the zero-cross state. Thus, in the zero-cross state in which detection deviation tends to increase, the detected currents Iu, Iv, and Iw are not used to calculate the d-axis command voltage Vd* and the q-axis command voltage Vq*.

On the other hand, the filter currents Iuf, Ivf, and Iwf have smaller current ripples than the detection currents Iu, Iv, and Iw, but are more likely to have phase delays than the detection currents Iu, Iv, and Iw. Therefore, when the filter currents Iuf, Ivf, and Iwf are set as the calculated currents Iup, Ivp, and Iwp, the phase delays of the filter currents Iuf, Ivf, and Iwf are the d-axis command voltage Vd* and the q-axis command voltage Vq*. likely to be included in In this case, there is a concern that the controllability of the motor 12 by the d-axis command voltage Vd* and the q-axis command voltage Vq* may deteriorate due to the phase lag.

Therefore, the current setting unit 61 sets the detected currents Iu, Iv, and Iw as the calculated currents Iup, Ivp, and Iwp when the zero-crossing state is not set. In this way, when the zero-crossing state is not set, the filter currents Iuf, Ivf, and Iwf are used to calculate the d-axis command voltage Vd* and the q-axis command voltage Vq* so that the controllability of the motor 12 does not deteriorate due to the phase delay. Not used.

The current zero-crossing range ZI is a permissible range set with respect to the zero-crossings of the detected currents Iu, Iv, and Iw. The current zero-crossing range ZI is set for the current values of the detected currents Iu, Iv, and Iw. The current zero-crossing range ZI extends along the horizontal axis indicating the electrical angle θ, and is in a state where it spans the zero-crossings of the detected currents Iu, Iv, and Iw. The current zero-crossing range ZI is common to the detection currents Iu, Iv, and Iw.

The detected currents Iu, Iv, and Iw change as the motor 12 is driven, and correspond to motor parameters. A motor parameter is a parameter that indicates the driving state of the motor 12 . In addition to the detected currents Iu, Iv, and Iw, the motor parameters include the d-axis current Id, the q-axis current Iq, the motor rotation speed Nm, the electrical angle θ, and the like. Current zero-cross range ZI corresponds to the parameter zero-cross range. The current zero-crossing range ZI is sometimes called a zero-crossing region, and the region other than the current zero-crossing range ZI is sometimes called a non-zero-crossing region.

As shown in FIG. 7, an upper limit value ZImax, a lower limit value ZImin, an intermediate value ZImid, and a range width ZIw are set for the current zero cross range ZI. Upper limit value ZImax, lower limit value ZImin, intermediate value ZImid, and range width ZIw are set for detection currents Iu, Iv, and Iw. Upper limit value ZImax indicates the maximum value of detected currents Iu, Iv, and Iw included in current zero-crossing range ZI. Lower limit value ZImin indicates the minimum value of detected currents Iu, Iv, and Iw included in current zero-crossing range ZI. The intermediate value ZImid is the middle value between the upper limit value ZImax and the lower limit value ZImin for the detection currents Iu, Iv, and Iw. In the current zero-crossing range ZI, the upper limit value ZImax and the lower limit value ZImin are set so that the intermediate value ZImid becomes zero.

The range width ZIw is the width of the current zero-crossing range ZI for the detection currents Iu, Iv, and Iw. Range width ZIw is the difference between upper limit value ZImax and lower limit value ZImin for detection currents Iu, Iv, and Iw. The range width ZIw is smaller than the maximum amplitude RA of the real current ripple. The amplitude of the actual current ripple is not uniform but varies in one cycle of the detection currents Iu, Iv, and Iw. The maximum amplitude RA is the largest amplitude of the actual current ripple in one cycle of the detected currents Iu, Iv, Iw. The maximum amplitude RA is, for example, the amplitude of the actual current ripple near the peaks of the detected currents Iu, Iv, Iw (see FIG. 4). In this embodiment, the maximum amplitudes RA of the detection currents Iu, Iv, and Iw are substantially the same.

In the current zero-crossing range ZI, for example, the upper limit value ZImax is set to 0.1 [A], the lower limit value ZImin is set to -0.1 [A], and the intermediate value ZImid is set to 0 [A]. In this case, the range width ZIw is 0.2 [A].

The control device 40 performs motor control processing. Motor control processing will be described with reference to the flowchart of FIG. The control device 40 repeatedly executes the motor control process at a predetermined cycle. The control device 40 executes motor control processing in synchronization with, for example, the carrier cycle. The control device 40 has a function of executing each step of motor control processing.

The control device 40 acquires the motor rotation speed Nm using the detection signal of the rotation sensor 29 in step S101 shown in FIG. Control device 40 obtains detected currents Iu, Iv, and Iw using the detection signal of current sensor 28 in step S102. The function of executing the process of step S102 in the control device 40 corresponds to the current acquisition section.

In step S103, the control device 40 performs zero-cross determination by the zero-cross determination section 62. FIG. In this zero-cross determination, it is determined whether or not the motor 12 is in the zero-cross state. For example, it is determined whether or not the detected currents Iu, Iv, and Iw are in the current zero crossing range ZI. When any one of the detected currents Iu, Iv, Iw is equal to or higher than the lower limit value ZImin and equal to or lower than the upper limit value ZImax, it is determined that any one of the detected currents Iu, Iv, Iw is in the current zero cross range ZI. . When the detected currents Iu, Iv, and Iw are in the current zero-cross range ZI, it is determined that the zero-cross state exists. If the detected currents Iu, Iv, Iw are not in the current zero-cross range ZI, it is determined that the zero-cross state is not present. The function of executing the process of step S103 corresponds to the parameter determination section and the current determination section.

If it is not in the zero-cross state, the controller 40 proceeds to step S104. In step S104, control device 40 sets detected currents Iu, Iv, and Iw as calculated currents Iup, Ivp, and Iwp. Control device 40 sets U-phase detected current Iu as U-phase calculated current Iup, V-phase detected current Iv as V-phase calculated current Ivp, and W-phase detected current Iw as W-phase calculated current Iwp. The function of executing the process of step S104 corresponds to the acquisition setting unit.

After step S104, the controller 40 proceeds to step S107 to calculate the d-axis current Id and the q-axis current using the calculated currents Iup, Ivp, and Iwp. In step S108, the control device 40 calculates the d-axis command voltage Vd* and the q-axis command voltage Vq* using the d-axis current Id and the q-axis current Iq. The function of executing the process of step S108 corresponds to the voltage command unit.

If it is in the zero-cross state, the controller 40 proceeds to step S105. In step S105, the control device 40 calculates the filter currents Iuf, Ivf and Iwf by the current filter 63 using the detected currents Iu, Iv and Iw. The function of executing the process of step S105 corresponds to the filter section. In step S106, control device 40 sets filter currents Iuf, Ivf, and Iwf as calculated currents Iup, Ivp, and Iwp. Control device 40 sets U-phase filter current Iuf as U-phase calculated current Iup, V-phase filter current Ivf as V-phase calculated current Ivp, and W-phase filter current Iwf as W-phase calculated current Iwp. A function for executing the process of step S106 corresponds to the calculation setting unit.

After step S106, the controller 40 proceeds to step S107, and calculates the d-axis current Id and the q-axis current Iq in the same manner as when the process proceeds to step S107 after step S104. After that, the control device 40 calculates the d-axis command voltage Vd* and the q-axis command voltage Vq* in step S108.

According to the present embodiment described so far, in the zero-cross state, the filter currents Iuf, Ivf, and Iwf with reduced pulsation with respect to the detected currents Iu, Iv, and Iw are set as the calculated currents Iup, Ivp, and Iwp. . In this configuration, the filter currents Iuf, Ivf, and Iwf are used to calculate the d-axis command voltage Vd* and the q-axis command voltage Vq* in the zero-cross state. Therefore, in the zero-crossing state, the pulsation of the detected currents Iu, Iv, and Iw is large, and the calculation accuracy of the d-axis command voltage Vd* and the q-axis command voltage Vq* is lowered. suppressed by Thus, in the zero-cross state, the motor control is less susceptible to large pulsations of the detected currents Iu, Iv, and Iw. Therefore, it is possible to suppress a decrease in the accuracy of motor control in the zero-cross state, and as a result, it is possible to improve the accuracy of motor control. By increasing the accuracy of motor control, it is possible to suppress an increase in driving noise and vibration of the motor 12 .

According to the present embodiment, it is determined whether or not the detected currents Iu, Iv, and Iw are in the current zero-cross range ZI as the zero-cross determination. With this configuration, it is possible to determine whether or not the motor parameters are within the parameter zero-cross range based on the detected currents Iu, Iv, and Iw and the current zero-cross range ZI. Further, in this configuration, the determination result as to whether or not the detected currents Iu, Iv, Iw are in the current zero-crossing range ZI is a result corresponding to the change mode of the detected currents Iu, Iv, Iw. Therefore, as the currents set as the calculated currents Iup, Ivp, and Iwp, the detection currents Iu, Iv, and Iw and the filter currents Iuf, Ivf, and Iwf are appropriately used according to the change modes of the detection currents Iu, Iv, and Iw. be able to.

In this embodiment, the filter currents Iuf, Ivf, Iwf are set as the calculated currents Iup, Ivp, Iwp when the detected currents Iu, Iv, Iw are in the current zero-crossing range ZI. Therefore, it is possible to suppress distortion in all of the detected currents Iu, Iv, and Iw, the d-axis current Id, and the q-axis current Iq. As for the d-axis current Id and the q-axis current Iq, the distortion of at least the third-order component can be reduced. For example, for the d-axis current Id and the q-axis current Iq, the tertiary one-sided amplitude 3thA [A] can be reduced. The tertiary one-sided amplitude 3thA is the one-sided amplitude of the tertiary component contained in the d-axis current Id and the q-axis current Iq.

For the control device 40, for example, a comparative example 10x different from the present embodiment is assumed. Comparative example 10x always sets the detected currents Iu, Iv, Iw as the calculated currents Iup, Ivp, Iwp regardless of whether the detected currents Iu, Iv, Iw are in the current zero-crossing range ZI. In Comparative Example 10x, the d-axis current Id and the q-axis current Iq, which ideally should be linear, tend to be distorted. Moreover, the distortion tends to increase due to the influence of detection deviation.

Comparing the third-order one-sided amplitude 3thA between the control device 40 and the comparative example 10x, as shown in FIG. It's becoming FIG. 10 shows the results of frequency analysis performed on the d-axis current Id and the q-axis current Iq for one cycle of the electrical angle θ. Frequency analysis includes FFT processing using FFT. FFT is the Fast Fourier Transform.

For example, when a third-order component is generated in the d-axis current Id and the q-axis current Iq, torque fluctuations are likely to occur in the motor 12 . Fluctuations in torque are likely to cause noise and vibration generated in the motor 12 . As for the motor 12, a large actual current ripple tends to cause a large detection deviation, and a large detection deviation tends to increase the tertiary components of the d-axis current Id and the q-axis current Iq. Also, if a motor with a relatively small inductance is called a low-inductance motor, the low-inductance motor is likely to cause an actual current ripple. For this reason, in a low-inductance motor, an increase in the actual current ripple results in an increase in detection deviation, which is likely to result in an increase in noise and vibration.

In contrast, according to the present embodiment, the filter currents Iuf, Ivf, Iwf are set as the calculated currents Iup, Ivp, Iwp for the current zero-cross range ZI in which the detection deviation is relatively large. In this way, in the current zero-cross range ZI, the filter currents Iuf, Ivf, Iwf in which the detection deviation in the current zero-cross range ZI is reduced more than the detection currents Iu, Iv, Iw are used as the calculated currents Iup, IvpIwp. Therefore, the d-axis command voltage Vd* and the q-axis command voltage Vq* can be appropriately set even in the current zero-cross range ZI in which the detection deviation of the detected currents Iu, Iv, and Iw tends to increase. This makes it possible to reduce the cubic components of the d-axis current Id and the q-axis current Iq, and as a result, the motor 12 can be driven silently.

The current zero-crossing range ZI is a dead zone from the viewpoint that the detection deviation of the detected currents Iu, Iv, and Iw is relatively large. In this dead band, the filter currents Iuf, Ivf, Iwf are used for the d-axis command voltage Vd* and the q-axis command voltage Vq* instead of the detection currents Iu, Iv, Iw. In this way, the detection currents Iu, Iv, and Iw in the dead band are less likely to affect the calculation accuracy of the d-axis command voltage Vd* and the q-axis command voltage Vq*. Distortion is less likely to occur. For example, the tertiary one-sided amplitude 3thA of the d-axis current Id and the q-axis current Iq is likely to decrease.

According to this embodiment, the range width ZIw of the current zero cross range ZI is a value smaller than the maximum amplitude RA of the actual current ripple. In this configuration, since the range width ZIw is set to a sufficiently small value, the filter currents Iuf, Ivf, and Iwf are set as the calculated currents Iup, Ivp, and Iwp, although the detection deviation is relatively small. It is becoming difficult for this to occur. Therefore, it is possible to prevent the deterioration of the controllability of the motor 12 due to the phase delay caused by the filter currents Iuf, Ivf, and Iwf from becoming more pronounced than the deterioration of the control accuracy of the motor 12 due to the detection deviation.

According to this embodiment, the intermediate value ZImid is set to zero in the current zero-cross range ZI. In this current zero-crossing range ZI, the filter currents Iuf, Ivf, and Iwf are calculated for both the cases where the detected currents Iu, Iv, and Iw swing to the positive side and the cases where the detected currents Iw swing to the negative side due to the actual current ripple. , Iwp can be properly implemented. Therefore, the manner in which the filter currents Iuf, Ivf, Iwf are set as the calculated currents Iup, Ivp, Iwp differs depending on whether the detected currents Iu, Iv, Iw swing to the positive side or to the negative side. can be suppressed.

According to the present embodiment, the detected currents Iu, Iv, Iw are set as the calculated currents Iup, Ivp, Iwp in the non-zero-cross regions. Accordingly, it is possible to suppress the occurrence of a phase delay due to the filter currents Iuf, Ivf, Iwf being set as the calculated currents Iup, Ivp, Iwp when the zero-crossing state is not set.

According to this embodiment, the d-axis command voltage Vd* and the q-axis command voltage Vq* are calculated from the calculated currents Iup, Ivp, and Iwp. In this configuration, by increasing the setting accuracy of the d-axis command voltage Vd* and the q-axis command voltage Vq* using the calculated currents Iup, Ivp, and Iwp, it is possible to increase the motor control accuracy.

<Second embodiment>
In the first embodiment described above, as the zero-cross determination, it is determined whether or not the detected currents Iu, Iv, and Iw are in the current zero-cross range ZI. In contrast, in the second embodiment, it is determined whether or not the filter currents Iuf, Ivf, and Iwf are within the filter zero-cross range ZIf as the zero-cross determination. Configurations, actions, and effects not specifically described in the second embodiment are the same as those in the first embodiment. In the second embodiment, the points different from the first embodiment will be mainly described.

As shown in FIG. 11, the control device 40 has a zero-cross determination section 620. In FIG. Filter currents Iuf, Ivf, and Iwf are input to zero-cross determination unit 620 . Zero-cross determination section 620 determines whether or not filter currents Iuf, Ivf, and Iwf are within filter zero-cross range ZIf. In the zero-cross state, the filter currents Iuf, Ivf, Iwf are in the filter zero-cross range ZIf. The filter zero-cross range ZIf includes the zero-crosses of the detection currents Iu, Iv, and Iw. The zero-cross determination section 620 corresponds to a parameter determination section and a filter determination section. Filter currents Iuf, Ivf, and Iwf correspond to motor parameters. The filter zero-cross range ZIf corresponds to the parameter zero-cross range. Zero-crossing determination section 620 is sometimes referred to as a filter zero-crossing determination section. In FIG. 11, the zero-cross determination unit 620 is illustrated as ZASf.

A filter zero-cross range ZIf shown in FIG. 12 is a permissible range set for the zero-crosses of the filter currents Iuf, Ivf, and Iwf. The filter zero-cross range ZIf is set for the current values of the filter currents Iuf, Ivf and Iwf. The filter zero-cross range ZIf extends along the horizontal axis indicating the electrical angle θ, and is in a state in which the zero-crosses of the filter currents Iuf, Ivf, and Iwf are crossed. The filter zero-cross range ZIf is common to the filter currents Iuf, Ivf and Iwf. The filter zero-cross range ZIf is sometimes simply called a zero-cross range or a zero-cross section.

As shown in FIG. 13, an upper limit value ZIfmax, a lower limit value ZIfmin, an intermediate value ZIfmid, and a range width ZIfw are set for the filter zero-cross range ZIf. Upper limit value ZIfmax, lower limit value ZIfmin, intermediate value ZIfmid and range width ZIfw are set for filter currents Iuf, Ivf and Iwf. Upper limit value ZIfmax indicates the maximum value of filter currents Iuf, Ivf, and Iwf included in filter zero-cross range ZIf. Lower limit value ZIfmin indicates the minimum value of filter currents Iuf, Ivf, and Iwf included in filter zero-cross range ZIf. The intermediate value ZIfmid is the middle value between the upper limit value ZIfmax and the lower limit value ZIfmin for the filter currents Iuf, Ivf and Iwf. In the filter zero-cross range ZIf, the upper limit value ZIfmax and the lower limit value ZIfmin are set so that the intermediate value ZIfmid is zero.

The range width ZIfw is the width of the filter zero-cross range ZIf for the filter currents Iuf, Ivf, Iwf. The range width ZIfw is the difference between the upper limit value ZIfmax and the lower limit value ZIfmin for the filter currents Iuf, Ivf and Iwf.

In the filter zero-cross range ZIf, for example, the upper limit value ZIfmax is set to 0.1 [A], the lower limit value ZIfmin is set to -0.1 [A], and the intermediate value ZIfmid is set to 0 [A]. In this case, the range width ZIfw is 0.2 [A]. The upper limit ZIfmax, lower limit ZIfmin, intermediate value ZIfmid, and range width ZIfw are set to the same values as the upper limit ZImax, lower limit ZImin, intermediate value ZImid, and range width ZIw in the first embodiment.

A motor control process executed by the control device 40 will be described with reference to the flowchart of FIG. In this embodiment, the order in which the control device 40 performs the processes of steps S104 and S105 is different from that in the first embodiment. After step S102, control device 40 proceeds to step S105 to obtain filter currents Iuf, Ivf, and Iwf.

After step S105, the controller 40 proceeds to step S201. In step S201, the control device 40 performs zero-cross determination using the zero-cross determination section 620. FIG. In this zero-cross determination, it is determined whether or not the filter currents Iuf, Ivf, Iwf are within the filter zero-cross range ZIf. If any one of the filter currents Iuf, Ivf, Iwf is equal to or greater than the lower limit value ZIfmin and equal to or less than the upper limit value ZIfmax, it is determined that any one of the filter currents Iuf, Ivf, Iwf is in the filter zero cross range ZIf. . When the filter currents Iuf, Ivf, Iwf are in the filter zero-cross range ZIf, it is determined that the zero-cross state exists. If the filter currents Iuf, Ivf, Iwf are not in the filter zero-cross range ZIf, it is determined that the zero-cross state is not present. The function of executing the process of step S201 corresponds to the parameter determination section and the filter determination section.

If not in the zero-cross state, control device 40 proceeds from step S201 to step S104, and sets detected currents Iu, Iv, and Iw as calculated currents Iup, Ivp, and Iwp. If it is in the zero-cross state, control device 40 proceeds from step S201 to step S106, and sets filter currents Iuf, Ivf, and Iwf as calculated currents Iup, Ivp, and Iwp.

According to the present embodiment, it is determined whether or not the filter currents Iuf, Ivf, and Iwf are within the filter zero-cross range ZIf as the zero-cross determination. With this configuration, it is possible to realize a configuration for determining whether or not the motor parameter is within the parameter zero-cross range based on the filter currents Iuf, Ivf, and Iwf and the filter zero-cross range ZIf. Further, in this configuration, the determination result of whether or not the filter currents Iuf, Ivf, Iwf are in the filter zero-cross range ZIf is a result according to the change mode of the filter currents Iuf, Ivf, Iwf. Therefore, the detected currents Iu, Iv, Iw and the filter currents Iuf, Ivf, Iwf are appropriately used as the currents to be set as the calculated currents Iup, Ivp, Iwp according to the change modes of the filter currents Iuf, Ivf, Iwf. be able to. Moreover, since the filter currents Iuf, Ivf, Iwf have less pulsation than the detected currents Iu, Iv, Iw, the d-axis command voltage Vd* and the q-axis voltage Vd* calculated using the calculated currents Iup, Ivp, Iwp It is possible to improve the calculation accuracy of the command voltage Vq*.

<Third Embodiment>
In the first embodiment described above, the zero-cross determination is performed using the detected currents Iu, Iv, and Iw as motor parameters. On the other hand, in the third embodiment, the zero-cross determination is performed using the phase angles θu, θv, θw as motor parameters. Configurations, actions, and effects that are not specifically described in the third embodiment are the same as those in the first embodiment. In the third embodiment, the points different from the first embodiment will be mainly described.

As shown in FIG. 15 , the control device 40 has a zero-cross determination section 621 . The zero-cross determination unit 621 determines whether the phase angles θu, θv, and θw of the detected currents Iu, Iv, and Iw are within the angle zero-cross range ZA. In the zero-cross state, the phase angles θu, θv, θw are in the angle zero-cross range ZA. In addition, the zero-crossing range ZA includes the zero-crossings of the detected currents Iu, Iv, and Iw. The zero-cross determination section 621 corresponds to a parameter determination section and an angle determination section. The phase angles θu, θv, and θw correspond to motor parameters and rotation angles. The angle zero-cross range ZA corresponds to the parameter zero-cross range. The zero-cross determination section 621 is sometimes called an angle zero-cross determination section. In FIG. 15, the zero-cross determination unit 621 is illustrated as ZAS.

The angle zero-cross range ZA is individually set for each of the detection currents Iu, Iv, and Iw. A plurality of angle zero-crossing ranges ZA are arranged along the horizontal axis. The plurality of angular zero-crossing ranges ZA include angular zero-crossing ranges ZA individually set for each of the detection currents Iu, Iv, and Iw. A plurality of angular zero-crossing ranges ZA are spaced apart from each other along the horizontal axis. The angle zero-cross range ZA is sometimes simply referred to as a zero-cross range or a zero-cross section.

As shown in FIG. 16, an upper limit value ZAmax, a lower limit value ZAmin, an intermediate value ZAmid, and a range width ZAw are set for the zero angle cross range ZA. The upper limit value ZAmax, lower limit value ZAmin, intermediate value ZAmid, and range width ZAw are set for the electrical angle θ. The upper limit ZAmax indicates the maximum value of the electrical angle θ included in the angle zero-crossing range ZA. The lower limit ZAmin indicates the minimum value of the electrical angle θ included in the angle zero-crossing range ZA. The median value ZAmid is the middle value between the upper limit value ZAmax and the lower limit value ZAmin for the electrical angle θ. The intermediate value ZImid is set to be the electrical angle θ at which the detected currents Iu, Iv, and Iw cross zero. For example, in the angular zero-cross range ZA set for the U-phase detection current Iu, as shown in FIG. 16, the electrical angle θ at which the U-phase detection current Iu becomes zero is set as the intermediate value ZAmid.

The range width ZAw is the width of the angular zero-cross range ZA for the electrical angle θ. The range width ZAw is the difference between the upper limit value ZAmax and the lower limit value ZAmin for the electrical angle θ. The range width ZAw is set to a size such that two angular zero-cross ranges ZA adjacent to each other along the horizontal axis are separated from each other. The unit of the upper limit value ZAmax, the lower limit value ZAmin, the intermediate value ZAmid, and the range width ZAw is [rad].

In this embodiment, the control device 40 performs zero-cross determination by the zero-cross determination unit 621 in step S105 of the motor control process. Here, it is determined whether or not the phase angles θu, θv, θw are within the angle zero cross range ZA. For example, for the detected currents Iu, Iv, and Iw, if any one of the phase angles θu, θv, and θw is equal to or greater than the lower limit value ZAmin and equal to or less than the upper limit value ZAmax, any one of the phase angles θu, θv, and θw is in the angle zero cross range ZA. When the phase angles θu, θv, and θw are within the angle zero-cross range ZA, the control device 40 determines that the zero-cross state exists. The control device 40 determines that the zero-cross state is not present when the phase angles θu, θv, and θw are not within the angle zero-cross range ZA.

According to the present embodiment, it is determined whether or not the phase angles θu, θv, θw are within the angle zero-cross range ZA as the zero-cross determination. With this configuration, it is possible to determine whether or not the motor parameters are within the parameter zero-cross range based on the phase angles θu, θv, θw and the angle zero-cross range ZA. Further, in this configuration, the determination result as to whether or not the detected currents Iu, Iv, and Iw are in the angle zero-cross range ZA is a result corresponding to changes in the phase angles θu, θv, and θw. Since the phase angles θu, θv, and θw are not parameters that repeatedly increase and decrease, but parameters that constantly increase, it is difficult to repeatedly enter and exit the angle zero-cross range ZA. That is, it is less likely that the determination of whether or not the detected currents Iu, Iv, and Iw are in the angle zero-crossing range ZA will be repeatedly affirmed and denied. Therefore, by using the phase angles θu, θv, and θw for the zero-cross determination, it is possible to improve the determination accuracy of whether or not the zero-cross state exists.

<Other embodiments>
The disclosure in this specification is not limited to the illustrated embodiments. The disclosure encompasses the illustrated embodiments and variations thereon by those skilled in the art. For example, the disclosure is not limited to the combination of parts and elements shown in the embodiments, and various modifications can be made. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses abbreviations of parts and elements of the embodiments. The disclosure encompasses the permutations, or combinations of parts, elements between one embodiment and another. The disclosed technical scope is not limited to the description of the embodiments. The disclosed technical scope is indicated by the description of the claims, and should be understood to include all changes within the meaning and range of equivalents to the description of the claims.

In each of the above embodiments, the current filter 63 may have an analog filter. The analog filter includes circuit elements such as coils, capacitors, and resistors. The current filter 63 may include at least one of a digital filter and an analog filter.

In each of the above embodiments, the motor control process may use either the electrical angle θ or the mechanical angle as long as it is a parameter related to the motor rotation speed Nm. The point is that the rotation angle should be used. For example, in the above-described third embodiment, either the electrical angle θ or the mechanical angle may be used for zero-cross determination. Further, in the third embodiment, it may be determined whether or not the phase angles θu, θv, θw are within the angle zero cross range ZA for the phase command voltages Vu*, Vv*, Vw*. Furthermore, in the third embodiment described above, the zero-crossing determination may be performed using the electrical angle θ for the filter currents Iuf, Ivf, and Iwf. For example, the electrical angles θ of the control filter currents Iuf, Ivf, and Iwf are referred to as filter angles θuf, θvf, and θwf, and the control device 40 determines whether or not the filter angles θuf, θvf, and θwf are within the angle zero-cross range. When the filter angles θuf, θvf, and θwf are within the angle zero-cross range, the control device 40 determines that the zero-cross state is present.

In each of the above embodiments, a plurality of motor parameters may be used for zero-cross determination. For example, a common zero-cross range may be set for a plurality of motor parameters, and the zero-cross state may be determined when at least one of the plurality of motor parameters is within the zero-cross range. For example, a common zero-cross range is set for the detection currents Iu, Iv, Iw and the filter currents Iuf, Ivf, Iwf, and both the detection currents Iu, Iv, Iw and the filter currents Iuf, Ivf, Iwf are in the zero-cross range. A determination may be made as to whether or not In this configuration, the zero-crossing state is determined when both the detection currents Iu, Iv, Iw and the filter currents Iuf, Ivf, Iwf are in the zero-crossing range. Furthermore, the control device 40 may have at least one of the zero-cross determination units 62 , 620 , 621 .

In each of the above embodiments, the width of the zero-cross range may be set to an extremely small value as long as the zero-cross range is set to include the zero cross of the current acquisition value. For example, in the first embodiment described above, in the current zero-crossing range ZI, the upper limit value ZImax and the lower limit value ZImin may coincide with the intermediate value ZImid. Also, the zero-cross range may be variably set according to the driving state of the motor 12 or the like. For example, in the above-described first embodiment, the current zero-cross range ZI may be set such that the higher the motor rotation speed Nm, the larger the range width ZIw.

In each of the embodiments described above, the zero-crossing determination may be performed at any timing in the motor control process. For example, the zero-crossing determination may be performed after the filter currents Iuf, Ivf, and Iwf are obtained as in the second embodiment. For example, the zero-crossing determination may be performed after the d-axis command voltage Vd* and the q-axis command voltage Vq* are calculated. The controller 40 generates a d-axis command voltage Vd* and a q-axis command voltage Vq* using the detected currents Iu, Iv and Iw, and a d-axis command voltage Vd* and a q-axis command voltage Vd* using the filter currents Iuf, Ivf and Iwf. Both the voltage Vq* and are calculated in advance. When the zero-cross state is determined, the control device 40 performs motor control using the d-axis command voltage Vd* and the q-axis command voltage Vq* calculated using the filter currents Iuf, Ivf, and Iwf.

In each of the above embodiments, the command voltages for calculating the calculation parameters may be the phase command voltages Vu*, Vv*, Vw*. Also, the command voltage may be calculated by a control method different from vector control. For example, the d-axis command voltage Vd* and the q-axis command voltage Vq* may be calculated by feedback control different from vector control. For example, the phase command voltages Vu*, Vv*, Vw* may be calculated by feedforward control.

In each of the above-described embodiments, the drive system 10 does not need to have the current sensor 28 as long as the control device 40 can acquire current acquisition values such as the detected currents Iu, Iv, and Iw. For example, the control device 40 may estimate the current acquisition value using the motor rotation speed Nm. In this case, the current acquisition value becomes the estimated value. Further, if the control device 40 can acquire the rotation angle such as the electrical angle θ, the drive system 10 does not have to have the rotation sensor 29 . For example, the control device 40 may estimate the rotation angle using the detected currents Iu, Iv, and Iw. In this case, the rotation angle becomes an estimated value.

In each of the embodiments described above, the motor rotation speed Nm may be calculated according to the current flowing through the motor 12 and the current applied to the motor 12 . In this case, the rotation sensor 29 may not be provided for the motor 12 . The control device 40 may calculate rotation information of the motor 12 without using the detection signal of the motor 12 .

In each of the above embodiments, the motor 12 need not be three-phase as long as it is an AC motor. Further, the inverter 30 may have a bridge circuit such as a full bridge circuit or a half bridge circuit as long as the inverter 30 is configured to supply AC power to the motor 12 . The bridge circuit includes switching elements such as arm switches 32a and 32b.

In each of the above embodiments, controller 40 is provided by a control system including at least one computer. The control system includes at least one processor, which is hardware. When this processor is referred to as a hardware processor, the hardware processor can be provided by (i), (ii), or (iii) below.

(i) a hardware processor may be a hardware logic circuit; In this case, the computer is provided by digital circuits containing a large number of programmed logic units (gate circuits). A digital circuit may include a memory that stores programs and/or data. Computers may be provided by analog circuits. Computers may be provided by a combination of digital and analog circuits.

(ii) the hardware processor may be at least one processor core executing a program stored in at least one memory; In this case, the computer is provided by at least one memory and at least one processor core. A processor core is called a CPU, for example. Memory is also referred to as storage medium. A memory is a non-transitional and substantial storage medium that non-temporarily stores "at least one of a program and data" readable by a processor.

(iii) The hardware processor may be a combination of (i) above and (ii) above. (i) and (ii) are located on different chips or on a common chip.

That is, at least one of the means and functions provided by the control device 40 can be provided by hardware only, software only, or a combination thereof.

In each of the above-described embodiments, vehicles on which the power conversion device 13 and the control device 40 are mounted include passenger cars, buses, construction vehicles, agricultural machinery vehicles, and the like. A vehicle is one type of moving object, and examples of moving objects on which the power conversion device 13 and the control device 40 are mounted include a train, an airplane, a ship, and the like, in addition to the vehicle. As the power conversion device 13, there are an inverter device, a converter device, and the like. As the converter device, there are an AC-input/DC-output power supply, a DC-input/DC-output power supply, and an AC-input/AC-output power supply. The power conversion device 13 and the control device 40 may be of a stationary type that is not mounted on a mobile body, instead of a mobile type that is mounted on a mobile body.

Reference Signs List 12 Motor 13 Power conversion device 40 Control device as motor control device 56 Two-to-three phase conversion unit as voltage command unit 62 Zero cross determination unit as parameter determination unit and current determination unit 620 . and U-phase detection current as a motor parameter, Iv... V-phase detection current as an acquired current value and motor parameter, Iw... W-phase detection current as an acquired current value and motor parameter, Iuf... U-phase filter current as a motor parameter , Ivf . W-phase calculated current, IuR: U-phase actual current as actual current, IvR: V-phase actual current as actual current, IwR: W-phase actual current as actual current, Vd*: d-axis command voltage as command voltage , Vq*... q-axis command voltage as command voltage, ?u... U phase angle as motor parameter, ?v... V phase angle as motor parameter, ?w... W phase angle as motor parameter, RA... maximum amplitude, ZI... Current zero-cross range as parameter zero-cross range ZIw Range width ZImax Upper limit ZImin Lower limit ZImid Intermediate ZIf Filter zero-cross range as parameter zero-cross range S102 Current acquisition unit S103 Parameter determination section and current determination section, S104...acquisition setting section, S105...filter section, S106...calculation setting section, S108...command section, S201...parameter determination section and filter determination section.

Claims (9)

A motor control device (40) for controlling a motor (12) with command voltages (Vd*, Vq*),
a current acquisition unit (S102) that acquires the current flowing through the motor as current acquisition values (Iu, Iv, Iw);
a voltage command unit (56, S108) for calculating the command voltage using the current obtained value as calculation parameters (Iup, Ivp, Iwp) for calculating the command voltage;
a filter unit (63, S105) that acquires filter currents (Iuf, Ivf, Iwf) from the acquired current values by filtering to reduce pulsation of the acquired current values;
a calculation setting unit (S106) that sets the filter current as the calculation parameter in a zero-crossing state including the zero-crossing of the current acquisition value;
A motor controller comprising: Determining whether the motor parameters (Iu, Iv, Iw, Iuf, Ivf, Iwf, θu, θv, θw) that change with the driving of the motor are within the parameter zero cross range (ZI, ZIf, ZA). 2. The motor control device according to claim 1, further comprising a parameter determination section (62, 620, 621, S103, S201) for determining whether or not the zero-cross state is present. 2. A current determination unit (62, S103) for determining whether or not the zero-cross state exists by determining whether or not the obtained current value is within the current zero-cross range (ZI). 3. The motor control device according to 2. In the current zero-cross range, the range width (ZIw) indicating the width of the current acquisition value is greater than the maximum amplitude (RA) of the pulsating component contained in the actual currents (IuR, IvR, IwR) actually flowing through the motor. 4. The motor control device according to claim 3, wherein is also a small value. 5. The motor control device according to claim 3, wherein in the current zero-cross range, an intermediate value (ZImid) between an upper limit value (ZImax) and a lower limit value (ZImin) for the current acquired value is zero. . A filter determination unit (620, S201) for determining whether or not the filter current is in the zero-cross state by determining whether or not the filter current is in the filter zero-cross range (ZIf). The motor control device according to any one of . The motor control device according to any one of claims 1 to 6, further comprising an acquisition setting section (S104) that sets the current acquisition value as the calculation parameter when the zero-cross state is not in effect. 7. The voltage command unit calculates a d-axis command voltage (Vd*) and a q-axis command voltage (Vq*) of a dq coordinate system as the command voltages using the calculation parameters. 1. A motor controller according to claim 1. A power conversion device (13) for converting power supplied to a motor (12),
a motor control device (40) for controlling the motor with command voltages (Vd*, Vq*);
The motor control device
a current acquisition unit (S102) that acquires the current flowing through the motor as current acquisition values (Iu, Iv, Iw);
a voltage command unit (56, S108) for calculating the command voltage using the current obtained value as calculation parameters (Iup, Ivp, Iwp) for calculating the command voltage;
a filter unit (63, S105) that acquires filter currents (Iuf, Ivf, Iwf) from the acquired current values by filtering to reduce pulsation of the acquired current values;
a calculation setting unit (64, S106) for setting the filter current as the calculation parameter in a zero-crossing state including the zero-crossing of the current acquisition value;
A power conversion device having

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